Furfural and related compounds are useful precursors and starting materials for industrial chemicals for use as pharmaceuticals, herbicides, stabilizers, and polymers. Conventionally, furfural can be produced from C5 sugars which have been obtained from hydrolysis of the hemicellulose contained in biomass. Typically, the hydrolysis of biomass is performed with aqueous acids at relatively high temperatures to obtain C5 and C6 sugars derived from xylan and glucan, respectively.
US Patent Publication No. 20110071306 discloses a method for the acid hydrolysis of carbohydrates in or from biomass, using a solvent system including an aqueous ether, where the ether forms a majority of the system.
In the biomass to furfural conversion process, it is known that metal halides can increase the rate of xylose decomposition, though without an increased furfural yield, especially when carried out in an aqueous medium. In the presence of ionic liquids, high metal salt loading (10%) increased yield enhancement has been reported for the conversion of fructose and glycose to hydroxymethyl furfural
There remains a need for a process that converts biomass to furfural, or xylose to furfural, at both increased rate and increased yield. It would also be desirable to prevent decomposition of the furfural once it is formed by such a process. Finally, it would be beneficial to reduce the large volume of acid currently used because of potential environmental and handling issues.